P0301 Misfire Code

I just bought an 08 and was playing around with my clutch start cancel switch in the driveway. I had it in neutral, pressed the switch and turned it on and immediately noticed shuttering and loss of power. I ended up throwing a P0301 code (cylinder 1 misfire). Turned it off and back on and it ran fine. Ordered an OBDII and plan on swapping coils/plugs. Does anyone have any idea if the clutch start cancel switch would have caused this somehow or if it was just coincidence.

 

Is the code still on? I would clear it by d/c the battery and see if it comes back.

 

Yeah, I haven’t started it since. My OBDII came in today. I wanted to get the freeze frame data off before I cleared it.

 

Coincidence totally.

 

Coincidence lol swap the coils on cylinder 1 and 2 and see if the code follows.. if not the spark plug would be the next candidate.. this happened to me a while back and on my 4.0 and the spark plug electrode had broken.

 

I pulled the coils and found the one that was misfiring was already replaced by the original owner, so I’m suspecting a bad coil. The rest were the OE Denso coils.

 

I would start fresh with new coils and plugs since your the second owner.

 

most likely will. Haven’t pulled the plugs yet but there was a little bit of oil residue on the coils. Debating on replacing valve cover gasket while I’m in there as well. Especially if the plugs have oil on them

 

The o rings for the spark plugs tubes are probably leaking oil.

 

I pulled the plugs, no oil on them. And they look good. They are NGK iridiums. The owner said they replaced them 20k ago. I did notice that when I went to pull the misfiring cylinder plug, it was very loose. I was able to unscrew it with my fingers.

 

Update: Swapped both the spark plug and coil pack from cylinder one to different cylinders, but still getting the P0301 code. The truck starts and runs great on a cold start, but if I drive it to the store, let it sit for 15 minutes, and try to start it again while it’s still warm, it will misfire. Happens intermittently and is difficult to repeat. Not entirely sure where to go next. Fuel injector issue?

 

That would be the next easiest theory to test.. swap that Injector with another and see if the code follows.

 

I’m not sure what kind of work that requires, or if I should tackle that myself.

 

Search around on here I wouldn’t imagine it’d be too hard

 

similar issue but different codes i am getting P0303 cylinder 3 misfire
P0300 random misfire detected.
I replaced all 3 new denso coils new wires and ngk spark plugs but still getting these codes.

 

Is cyl #3 the only reported misfire?
It could be an injector, but if multiple cylinders are miss firing, I’d look somewhere else first.

 

Mine is consistently cylinder 1. I never threw a random misfire code.

 

Motor needs 3 things to run:
1) a proper air / fuel mix
2) compression
3) correctly timed spark

if it’s got that it HAS to run, it has no choice. You say you have ruled out faulty spark plugs / coils so next you swap injectors to see if the code follows. If it doesn’t you check compression which is very easy to do on your motor. Just remember to pull EFI fuses first.

 

Understood, thanks! I’m pretty convinced that it’s an injector issue. I have a warranty that will cover them, so it is at the mechanic now. Waiting on the final diagnoses. Will update

 

Alright perfect thank you for help looks like i am gonna have to replace fuel injectors and will take out efi fuse as-well.